Category : Files from Magazines
Archive   : VOL8N22.ZIP
Filename : SETJMP.ASM

CODE SEGMENT BYTE PUBLIC
ASSUME CS:CODE
PUBLIC SetJmp, LongJmp

SetJmp PROC FAR
PUSH BP
MOV BP, SP
LES DI, 6[BP] ; Get address of JumpBuffer
CLD
LEA AX, 6[BP] ; Save SP
ADD AX, 4
STOSW
MOV AX, SS
STOSW ; Save SS
MOV AX, 4[BP]
STOSW ; Save CS
MOV AX, 2[BP]
STOSW ; Save IP
MOV AX, [BP]
STOSW ; Save BP
MOV AX, DS
STOSW ; Save DS
XOR AX, AX ; Return a value of 0 from SetJmp
POP BP ; Restore previous frame pointer
RET 4 ; Clean up stack and return
SetJmp ENDP

LongJmp PROC FAR
PUSH BP
MOV BP, SP
MOV BX, 6[BP] ; Get the return code
CMP BX, 1 ; If it is zero then return a value of 1
ADC BX, 0 ; so that LongJmp never returns 0
LDS SI, 8[BP] ; DS:SI points to JumpBuffer
CLD
LODSW ;Restore SS
MOV SS, [SI]
MOV SP, AX ;Restore SP
LODSW
LODSW
PUSH AX ;Push CS and IP onto the stack
LODSW
PUSH AX
LODSW
MOV BP, AX ;Restore BP
LODSW
MOV DS, AX ;Restore DS
MOV AX, BX ;RetValue in AX
RET ;Return with CS:IP from JumpBuffer
LongJmp ENDP
CODE ENDS
END